1. Field of the Invention
The present invention is in the field of cleaning machines and more specifically relates to a machine that employs both an air blast and a vacuum to clean asbestos particles from the brake drum of an automobile.
1. The Prior Art
It is now widely recongized that it is hazardous to a person's health to inhale particles of asbestos. Nevertheless, at this time, many automobile brake linings are made from compositions that include asbestos. As the brakes are used, the brake lining material is worn to dust, and some of this dust remains trapped in the brake drum and associated parts.
Before the hazard was understood, automobile repairmen normally used a blast of compressed air to blow the asbestos dust particles out of the brake assembly. When this was done, the particles were dispersed throughout the workplace with the result that the workers breathed appreciable quantities of asbestos dust, and later became ill.
A number of inventors have addressed the problem of how to remove the asbestos particles from the brake assembly without at the same time dispersing those particles throughout the air of the workplace.
These inventors have, almost without exception, included as part of their inventions a hood within which an air nozzle directs a stream of air at the brake, and the resulting cloud of particles is contained by the hood. Possibly the earliest patent is U.S. Pat. No. 3, 222,707 issued Dec. 14, 1965 to Allenbaugh. Allenbaugh is notable for his use of a venturi jet for obtaining a vacuum to dispose of the cloud of suspended particles.
Other known prior art includes U.S. Pat. Nos. 3,510,905 issued May 12, 1970 to Bannert; 3,731,340 issued May 8, 1973 to Pitre, Sr.; 3,972,089 issued Aug. 3, 1976 to Parks; 3,978,547 issued Sept. 7, 1976 to Lawson; and 4,205,412 issued June 3, 1980 to Weber. By the time of Weber's patent, the health hazardous aspects of asbestos dust had become widely recognized, and the Weber patent is noteworthy in disclosing a system in which all of the incoming air is washed by a water spray before being discharged into the atmosphere.
Other prior art includes French published application No. 2,346,061 published Oct. 28, 1977 by Aspirateurs Nilfisk, S.A. and West German published application DE No. 29 36 779 A1 of Fischer, published Apr. 1981.
The design of the present invention includes several features which do not appear to be known in the prior art, and which permit superior performance to be obtained.